Duhok dam reservoir is situated in Duhok city, Iraq. It is an artificial reservoir which supplies water for crops land and orchard around the canal throughout its path. The objective of this investigation is to assess physical, chemical and microbiological aspects of aquatic ecosystem in the lake. The water quality variables (water temperature, pH, EC, total dissolved nitrogen and phosphate, SO 2 , BOD 5 and microoganisms) were being measured seasonally during 2011. The results reported that high conductivity and sulphate concentrations were recorded during different seasons. Heterotrophic plate count and faecal colifom exceed Iraqi and WHO standards for drinking purposes. Statistically, no differences were found between studied sites for all variables. Microbiological isolates, counts, total occurrence and diversity index were more in sediment than in water samples. The occurrence of mycobiota was surveyed by three isolation methods 19 fungal species assigned to 14 genera were isolated. The most frequent species in order were: Aspergillus spp., Penicillium spp. and Eurotium spp. The occurrence of keratinophilic fungi was detected in the sediment by hair baiting method The most frequent genera isolated in this study were Chrysosporium spp. , Trichophyton spp. and Microsporum spp.

The aquatic Heptageniidae family of Ava-sheen branch (Greater Zab Tributary) in Duhok Governorate/ Iraq was studied. Samples were collected using Surber stream sampler to study their diagnostic morphological characteristics and molecular phylogenetic profile using a nuclear gene 16s ribosomal RNA. The morphological and molecular identification supported that the three species, Epeorus longimanus, Heptagenia elegantula and Ephemerella cornutus belong to Heptageniidae family, while the molecular results also confirmed the monophyletic origin of these three genera.

An experiment was conducted to assess the effect of different concentrations of the insecticide carbaryl on histological and biochemical parameters including (SOD, GSH, rGSH, CAT and MDA) on gills tissue of freshwater mussel Unio pictorum for 96 hours. Significant increase in SOD and rGSH activities was observed in a concentration- dependent manner. However, statistically significant decrease in GSH levels was observed only at highest concentration. MDA levels reached higher rate at high concentration of carbaryl treated group. Mussels show behavioral responses during exposure by exhibiting increase in duration for shell closure and increase in mucus secretion. The histopathology of gills indicated that higher doses of carbaryl resulted in massive destruction in normal architecture of gill tissue. Molluscs accumulate contaminants in their body tissues and thus are used as bio-indicator for evaluating water quality and habitat degradation.

The population of Ephemeroptera was studied in three selected stations of Rawanduz River (Gali Ali Beg water fall, Rawanduz River and after the junction of these two waters) during the three seasons of spring, summer and autumn in 2016. In addition,sixteen physicochemical parameters (pH, EC, turbidity, DO, BOD5, NO3, TDN, TDP, HCO3-, Hardness, Ca2+, Mg2+, Na+, K+, Cl-, SO42-, Na% and SAR) of water in these stations were estimated and used to calculate the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI). Eleven species of aquatic insects were identified,which belong to four families of the order Ephemeroptera. Three of the studied species are described for the first time. According to water quality index, the water was ranked as poor for drinking and marginal for irrigation purposes.

Phycology, mycology and physicochemical parameters of some artificial open sand mine ponds in Kalak sub district-Duhok-Iraq were investigated, for a period of six months from July to December-2015. Water samples were collected monthly basis and analyzed for measuring of water temperature, turbidity, pH, electrical conductivity, nitrate, nitrite, ammonium, orthophosphate, dissolved oxygen and biochemical oxygen demand. Concerning algal communities, the results showed that the sixty taxa were identified in samples collected during the study period. They belong to classes Cyanophyceae (18 taxa) with percentage composition of 30%, Chlorophyceae (20 taxa) with percentage composition of 33.3%, Euglenophyceae (2 taxa) with percentage composition of 3.4%and Bacillariophyceae (20 taxa) with percentage composition of 33.3%.According to Shannon-Weiner index, species diversity varied from (2.053to 3.895bits/ind), in pond 3 and in July had the highest diversity were recorded. Concerning to Jaccard similarity index, the highest percentage of similarity to algal community observed between site2 and site 4 reached to 32%. The diatoms were the most noticeable algae in all ponds which represented by Cyclotella, Navicula, Syndra and Cymbella with respect to the frequency of occurrence and number of individuals in all ponds. The diatoms showed their best growths through this study. The dominant of Chlorophyta and Cyanophyta followed by Study algae and fungi interaction in some artificial open sand mine Ponds in kalak sub district-duhok, iraq.